The heat stroke that José Delgado suffered six years ago after working in a sweet potato field in South Florida left him with damaged kidneys. It happened again two years later. His doctor, he said, warned that his heart might not survive another episode.

He is 75 now and still waking up at 5:30 a.m. six days a week to labor in the fields, putting his wizened body through more and more days of extreme heat. Last year, the National Weather Service issued heat advisories for Miami-Dade County on 41 days. This year, it has done so on 63 days, most recently on Sept. 30. Over two days in May, the heat index reached 112 degrees Fahrenheit, breaking the previous daily record by 11 degrees.

Mid-October is typically the start of a drier, somewhat cooler period in South Florida. For Mr. Delgado, it is a moment of relief. But it is also a time to reflect on what could have been.

Mr. Delgado used to hope that his story would move policymakers to enact heat protections for outdoor workers. He no longer believes it will.

“They’re in cool air all day,” he said of lawmakers, his voice tinged with bitterness. “They don’t think about who labors to put food on their table.”